/*=========================================================================
 *
 *  Copyright NumFOCUS
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *         https://www.apache.org/licenses/LICENSE-2.0.txt
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *=========================================================================*/

#include "itkSphereSignedDistanceFunction.h"

/**
 * This module tests the functionaliyt of the SphereSignedDistanceFunction
 * class and its superclass ShapeSignedDistanceFunction.
 *
 * In particular, it creates a SphereSignedDistanceFunction object
 * cast it to a generic ShapeSignedDistanceFunction object.
 *
 * The shape parameters are set at radius of 5 and center of (0,0).
 * The signed distance is evaluated at several point and compared
 * to expected values. The test fails if the evaluated results is
 * not within a certain tolerance of the expected results.
 *
 */
int
itkSphereSignedDistanceFunctionTest(int, char *[])
{
  using CoordRep = double;
  constexpr unsigned int Dimension = 2;

  using FunctionType = itk::ShapeSignedDistanceFunction<CoordRep, Dimension>;
  using SphereFunctionType = itk::SphereSignedDistanceFunction<CoordRep, Dimension>;
  using PointType = FunctionType::PointType;
  using ParametersType = FunctionType::ParametersType;

  auto sphere = SphereFunctionType::New();

  // cast it to a generic function
  const FunctionType::Pointer function = dynamic_cast<FunctionType *>(sphere.GetPointer());
  sphere = nullptr;

  // we must initialize the function before use
  function->Initialize();

  ParametersType parameters(function->GetNumberOfParameters());
  parameters.Fill(0.0);
  parameters[0] = 5.0;

  function->SetParameters(parameters);

  std::cout << "Parameters: " << function->GetParameters() << std::endl;

  PointType point;
  function->Print(std::cout);
  std::cout << function->FunctionType::GetNameOfClass() << std::endl;

  for (double p = 0.0; p < 10.0; p += 1.0)
  {
    point.Fill(p);
    const FunctionType::OutputType output = function->Evaluate(point);

    std::cout << "f( " << point << ") = " << output << std::endl;

    // check results
    const CoordRep expected = p * std::sqrt(2.0) - parameters[0];
    if (itk::Math::abs(output - expected) > 1e-9)
    {
      std::cout << "But expected value is: " << expected << std::endl;
      return EXIT_FAILURE;
    }
  }

  std::cout << "Test passed." << std::endl;
  return EXIT_SUCCESS;
}
